Process for making flexible protective shields



Jan. 16, 1945. J. sTRoBlNo 2,367,446

PROCESS FOR MAKING FLEXIBLE PROTECTIVE SHIELDS Filed Nov. i3, 1941lNvE-NTOR. Louis J. Srobino ATTORNEY Patented Jan. 16, 1.945

PROCESS FOR MAKING FLEXIBLEv PROTECTIVE SHIELDS Louis J. Strobino,Bethel, Conn.

Application November 13, 1941, Serial No. 419,012

1 Claim.

This invention relates to improvements in process for making `flexibleprotective shield.

More particularly it relates to the making material for flexible shieldsfor protecting a human part, as a hand or body, for obstructing and thusretarding the onset of `Xrays, or heat, or a chemical reagent, or someother particular energy whose reaching the shielded area may beundesirable.

The invention is herein illustratively described for gloves to shieldX-ray operators hands. In this as in other fields of chemical orphysical energy, ordinary gloves are not suiiicient to stop theparticular inimical energy against which the invention is directed; andthe adding of layers of obstructive material, as heretofore known,produces inilexibility that restricts the manipulative power of thewearers hands, as by disabling the hand from writing, dulling itssensitivity to touch through `the glove, diminishing its operativeskill, and slowing the operators action. Similar needs exist in otherfields, as where the material being handled has a high temperature; oris productive can be so much staggered, relative to each other, and beso deeply permeating the body ofwthe sheet, that every space betweenadjacent particles is, at some depth or other, underlain or overlain byother particles, so that all rays that strike in encounter them asobstructions.

In the case of a shield against X-rays, the glove material, such asleather or textile fabric, be-

of chemical reaction, as in the case of materialA handled by workers inlelectro-plating, etc. X-ray shields it has been proposed to impregnategloves with lead acetate, and to cover this with a layer of rubber tohold the acetate from escaping in moisture, but this makes the materialstiff; and without the rubber the lead ace- `v tate is fugitive inmoisture. The combining of satisfactory flexibility with satisfactoryopaqueness to inimical energy has been many times attempted, but so faras I am aware has not hitherto been adequately solved.

The application for this patent is a continuation in part of myapplication, Serial 372,160, filed December 28, 1940.

The shield of the invention combines flexibility With resistance byconcentrating insolubleV resistant particles within a porous sheetmaterial that is inherently exible, as leather or cloth or felt, so thatthe inherently flexible sheet takes on also a character of beingconcentratedly obstructive to the passage of 'the particular en muchfrom the flexibility ofA the sheet. They@ For comes permeated with solidparticles of lead, or an insoluble lead salt, or some other heavy metalor salt which is an obstacle to the X-rays. In the case of material forhandling hot steel, or hot castings, the solid particles dispersedthrough the sheet body are of a substance selected as being a poorconductor of heat, as, forvexample, lamp black, or diatomaceous earth(diatomite) or any of numerous salts.l In any case wherethe shieldingmay encounter water or perspiration when in use, the dispersed materialmay be one that is insoluble in water, as, a salt that has beenprecipitated in situ from aqueous solution within the leather or otherflexible sheet. Also some liquids and semi-liquids may be used,especially insulating waxes, which become liquid at elevatedtemperatures.

l'or resisting chemicals, especially acids and bases, there may beimpregnation of leather with amphoteric hydroxides, precipitated insitu. Among these are aluminum hydroxide, zinc hydroxide and chromiumhydroxide.

The invention attains these results by starting with a duly flexibleporous sheet, and lling that sheet with finely divided opaque materialof the variety chosen. The word opaque as herein used refers only toopacity or obstructiveness to the particular influence which is to bestopped, as X-rays or temperature or a chemical reagent,` and has nosignificance as to the transmission of light or vision.

The sheet material may be selected from among tissues of any suitablestrong yet porous sort, examples being found'in leather, and in wovenand felted fabrics.

The opaque particles or the reagents which y produce them are to bepounded into the sheet body in a fluid state of dispersion, being eitherminute solids dispersed in liquid or being fully liquid in solution. Inthe latter case there is production of solid particles bychemicalreaction, of two solutions, with each other within l the body of thesheet.

If introduced as solids, the extreme fineness of the solid particles,and the pounding that occurs as the sheets tumble' in their penetrative.fluid vehicle, gets them into the microscopic intive character of thehydroxide particles retards"" onset of an acid or alkali in its.progressl toward the wearers hand.

For obstructing X-rays, lead can be introduced Illustratively, such twosolutions may be lead acetate and sodium bromide, each solution beingintroduced separately by tumbling the tissue in it and then drainingaway its excess above what has been absorbed by the tissue. Either maybe put in rst, and after the other is put in the pre-f cipitatio-n oflead bromide occurs in finely divided form. This process may be repeatedseveral times, .until Vthe skin willnotabsorb and hold anymore. i

Either of these lead-impregnating methods may sbe used alone, or bothmay be used, cumulatively, the one being applied after the other, toadditof the @body of lead, lead salt or other obstructive. substancewhich the leather or other tissueca-n thus be made to carry. Followingthis by combined and simultaneous tumblingfil'exing and beating. Anysubstance can-.beused,'. which. is

obstructive to the attack that is to be minimized,

if capable of being introduced into the "flexible" A.tissue feitherfinnely ydividedl solider colloidal ,Which'protection of,` the sortdescribed may be desired',v rv

For peperone.. the .opaque `:material within the sheetrnaterial; theporous tissue, as skins, fabrics or other sheetsgristumbledrepeatedlyfinto and out-fof the 'laden liquid: vehicle. :It isconvenient yto do thisin a. rotary .'drurn` or other container havinginternal pegs or ridges, this being partly 'iilledwith theliquidwhichicarries, into .the body of the tissue,fthe "opaquemateriaL'either Vactually or potentially.;v `In a process-which Ihavefound l good,rtl'1`e material/for opacity ofv -X-Lray is` metallic.lead, veryfnely divided `andV :dispersed in meshl screen, fandmikedwithafwater. metallic ,lead gOesfinto suspension in'.` the Water,andthe tum.-

bling of it in the Waterwvorksit .into the interior ofV alskina A sal-tlWhichicanfbe introduced similarly is lead oxide,fnot quite sogood'. Thevturnbling iinvolves ar: repeated lifting of the itissue from theliquid-and"droppingiti backV with concurrent eXi'ng-, and Withfimpactsof tissuel 'against liquid/and of wooden sknobs i or ridges againstliquid and tissue. ii f,

This'action` isin general; a beating together of the `liquid andthetissue inv a bodyfof thefliquid' exceeding Whatthe `tissue, canfabsorb..It can-be executed with"othc-:rv apparatuazas by a yreciprocatingplungerI Working as; afbeatez." in ra. stationary container holding lasuitable'. quantity oiythe fluid. Apparatus of a type already .knownfforVWashing clothescan bef used for this',Y Or it' can be done by hand.

For the making of' a sheet resistant material, suitable for gloves forsteel; workers, and for Welders,v etc., the impregnation' can besimilarly carried'l out.` The `solid opaque'ior insulating` ma- 'iteria-LWhich'forthisuse may be lamp black or pulverized diatomite,dispersos in Water in the .tumbling drum` vsuclrliin'eness and. sothoroughly that it goeslinto ai stateof suspension throughy out the body4of: the Water, andsentersrthe tissue* with the Water.

Howeverfthe intemalfdepositing" ofl anely divided solid Ycan-beeflectedb-y impregnating'the `tissue".'=.\ic:ce.ssively withI solutions whichreact together so asv to precipitate; the opaque substance.

the"imp'regnated sheet is to be dried, and the contained :liquidevaporated out.

Foropacity or insulation against heat, there are numerous salts that canbe carried into the tissue-by the `method ,-:abovey described' for lead.SimilarlyV `withy an amphoteric-:lhydroxideiwhich will resistreactivepenetratioirby, acidic and basic chemicals. And this can be madeby precipitation: .from reagents. i

In all casesrwashing .and drying may-follow; and; in, cases where thetissue `is a skin-,1 the fat li'quoring andI other' usual. stepsmayrbeutaken in the manner of tanners, in any suitable Way. After theleather is .fnished surface vcoatings of the opaquematter-.fmay -beadded, andfsealing films applied over them. 1 The compositejilexibleopaquesheet materia-1 is :then ready to -be made into any:suitable-articles, Tas gloves, or tor be used innsimple sheet form;

The accompanying `drawing?represents appa.- ratuswth'atmay be used in:introducing, into a exible lporous-sheet,.the lead or other obstructingsubstanceaor the `reacting `compounds from whichthe substanccfis`precipitated; also'aI product of. the invention; in sheet` material;andfan embodiment yof: that materialtin a glove;y but it willbeunderstoodth'at the invention. .is not limited: tn the particular.showing hereinV made for illustrationY of; the "principles'z involved.

It isiintendedthatythe patent shall'cover; by suitable"expression'inithe appended claimy what'- ever features of' patentable novel-ty*exist in the invention disclosed."A

" lIn the accompanying drawing:l

Figurerl is a View1 offthepalmside of al glove made according totheprocess4 of the invention;

Figure 2fis 'a sectioniorr the line 2-2f of Figure 1, on a'larger scale;:diagrammatically showing structure of a composite'glovexwhich.has'three plies of. opaque "sheetszc Figure" is ayfragmentfon a. stilllarger scale showing diagrammaticallyrthestructure of one of the pliesof Figure' 2; and

I"Figure 4 is a'vertical section through a drum suitable for working'they `process of the invention.

The fdrawingfillustrates an application 4of `the invention'in the`ileldotprotectionxfor an oper ators hand from'X-rays.A

In Figure 3,' the middle element |01 represents an animal skin, but itmay be cotton or Woolen fabric, Lor other flexible "tissue sheet whichis somewhat porous;v and the small dots I2 distributed'lall throughthis'element indicate the presence ofl small particles Otlead or othersubstances Which is opaque 'toi X-rays, thickly disperse'd'throughoutthe whole of the element ID.

Covering each face ofthe skinv is ajlayer I4 o'f adhesive;vvhi'chmayLzbev latex. that` has, been sprayed upon it.v Outside of--this`, oneach side, is a layer I6 representing a material such as is used forcarrying pigment, throughout which are distributed small dots I8representing X-ray o-paque material in finely divided condition, which 5may be the same as or different from the kind of material represented bythe dots I2. And outside of this is a layer 20 which represents a thincoating of lacquer or other flexible smooth finish applied byI sprayingor otherwise. l

The element I0 is inherently exible and may, for example, be sheepskinor split pigskin. The superficial lm I4 should also be flexible. If ahigh degree of flexibility is desired the latex mentioned as possiblyconstituting this element may 1 be found to introduce more stiffnessthan is wanted, when it is dry. In that case this element should beomitted, and the opaque material, which it would be carrying if present,can, if needed, be added by other means, to that carried 2 within thebody of the sheepskin. The element IE is a lm of drying oil or the like,made exible by the inclusion of glycerine or the like and carrying theinely divided opaque material dispersed throughout its body. This holdsitself naturally 2 to the latex, or to the element I0 if the latexelement I4 should be absent. The inherently flexible coating of lacquer20, which adheres to its outer face, strengthens ity against breakage byflexure.

In Figure 2, which shows a cross section through the Wrist of ashielding glove 30, seen in Figure l, the glove has a plurality of plies22, each being such as the whole of the unit shown in Figure 3,containing a basal flexible sheet I0 with opaque 3 substance I2dispersed through that sheet by the process of tumbling hereinafterdescribed with reference to Figure 4. Each of the represented threeplies 22 is a complete glove. These are nested successively within eachother, and another complete glove 24 inside of them all is made of somethin easy-slipping textile material such as rayon. These four plies areheld all together by one or more lines of stitching 26 at the wristedgeof the glove. The maker of the glove has considerable latitude indesigning the details, contents and construction of each unit 22, -asthe tissue I0 of Figure 3 may be either skin or manufactured fabric, andthe layers IG are merely for holding additional thickness of the oopaque dispersion, while the layer 20 is for physical retention andenclosure of the opaque material.

For easy flexibility the successive plies lie loosely y over each other,so that each can slip somewhat D relative to its neighbors, when ngersbend.

The impregnating step is best executed with penetrating fluids of lowviscosity. Mixing water with the described very i'lne metallic leadhelps carry the lead into the porous sheet, with entrance; of water. Ifthe lead is introduced in a form which is not actually metallic, as inlead acetate, that aqueous solution and the aqueous solu- If thepenetration is eiected in a tannery, in drums such as are used there,the interior of the drum will have pegs several inchesl ylongdistributed a foot or so apart; and skins of standard size will thus becarried up and dropped repeatedly, flexing the skin until the uid andwhatever is dispersed through it has fully penetrated, which may be in ahalf hour, or less. The pounding loosens the bres in the skin, somewhat,and moves them about a little relative to each other, and thus makesspaces into which the solution goes more readily than if the leatherwere merely immersed.

In the diagram of drum 32 herein shown, the elements |24 may representthe pegs of the tanners drum above mentioned, or, instead of pegs theymay be considered to represent a series of ridges which extendinteriorly from end to end of the drum, equi-spaced around itsperiphery. Such ridges may be planks set on edge, constituting largeslats, to perform the same function as the pins, before mentioned,engaging and carrying the skins up, and then dropping them, withrepeated exing and pounding of the skins so that the solution goesreadily into their pores.

For the impregnating, a strong or concentrated solution is advisable,one in the region of 50% saturation in water being useful at atemperature in the region of 12o-125 F.

The precipitation occurs wherever the sodium bromide, or potassiumiodide, if that be used, finds the acetate, within or on the surface ofthe skin. The body of liquid outside the skin facilitates the tumbling,and helps to avoid injury to the skin in the tumbling. The precipitatedlead salt coats the leather bres and is adsorbed thereon ratherstrongly.

In practicing the invention to make shields against ultra violet rays,which may be important in various industries, one example being inwelding, metallic dusts, such as dusts of copper, aluminum or iron, havebeen found suitable. Any such dust may be incorporated in leather toblock the passing of ultra violet rays.

Diatomic earth of neness to pass through a screen of 600 mesh, more orless, has a higher insulating index than ordinary leather; and this,like the said metallic dusts, can be impregnated into leather, forexample, or into other tissue, according to the method herein describedfor the impregnation of tissue with lead dust. Leather thus loaded withdiatomic earth has been found tion of the reagent which is toprecipitate it, are u.)

to be used with a fluidity approximating the thinness of water, ifoptimum eiect is desired. In either case the resulting insoluble powderof lead or other opaque substance is held entangled physically withinthe sheet of tissue, after the 7 liquid has been evaporated; and itsescape, when somewhat loosened by repeated flexure of 'the holdingsheet, is prevented by the -continuous supercial sheet of film and ofclose woven textile.

to withstand 600 to 800 F. of dry heat for short intervals withoutimpairment.

Flexible shields for protection against other inimical emanations can bemade with use of suitable materials by the methods herein disclosed. Forexample large amounts of aluminum hydroxide can be made to enterleather, by procedure similar to that for impregnating leather with leaddust.

Easier penetration of the preferred kind of skin, as pi'gskin orsheepskin, is had by rst degraining the skin, as by splitting, shaving,bucktailing, suedi-ng or other method. The tannings may be by anymethod, but it is best if the method chosen is one which makes a softspongy leather, preferably chrome tanning. The presence of theintroduced solid material makes it advisable to use unusually largeamounts of fat liquor to keep the leather soft, because of the tendencyof finely divided powders to absorb oils and fat liquors. Thisaugmentation Vof fat liquor yoperates toward increasing the strength ofthe product, counter- ,acting Weakness Whchfthe abnormal; separatingable to the destructive rays, a body of Water 1.0

which has the property of readily penetrating the pores in said sheet,and ay quantity of solid lead particles in neness of the order of atleast 300 mesh,zdispersing said leadv particles in said body of water-toprovides concentratedsuspensiouof lead .particles :suspended'in water;Ythereafter tumbling the sheet in. a volume of(A the Asuspension*exceeding that which the sheet can-absorb,

thus causing the suspension` of water-and-.flead particles to thoroughlypermeate the porous' sheet so that the lead particles are physicallyentangled Within and throughout th'e interflbrous pores-of the sheet,and thereafter removing the `water from the sheet thereby leaving thelead-particles physically entangledwithin and throughout 'the thicknessofthe sheet. i

LOUIS yJ STROBINO. E l'

